The Age of Discovery, Chapter 6: The Water Flea

Day 3: 1430 hours...

Emerging from the region of shadow, sunlit water fills our forward view with the now familiar close-yet-distant blur of watery blues, greens, and soft yellows.  I post Barron to the crow’s nest to keep watch, and am about to order Gyro to take us up a hundred centimeters when the engine master’s rumble bellows over the voice pipe. 

“Collision!  Close the shutters!  Repeat: collision!”

Gyro throws the release for the crash doors.  The steel plates slam down over the glass panes of the pilothouse an instant before we hear a thunderous crunching sound, and are thrown forward against controls and railings.  The noise of the impact reverberates through the ship – an out-of-tune timpani. The screech of metal against something of similar hardness provides an upper register to this chaotic chord.  Then all becomes eerily quiet.

“I think we hit something,” offers Lyra, pulling herself up from the deck, her wry conclusion left hanging in the air.

“Or it hit us,” counters Gyro. 

“Either way,” I say, “let’s make sure we didn’t spring any leaks.  You know the protocol – I want eyes on every seam, every rivet, bow to stern.  On the double!”

Once determined that we’ve suffered no breech, I order the crash doors un-shuttered.   As the corrugated leaves of iron fold away we finally see the object that had collided with Cyclops.

“Daphnia pulex!” heralds Lyra with delight.  “But more commonly known as the water flea.  But nobody has ever seen Daphnia like this before!” 

I recalled seeing my first Daphnia in a general biology class at the Naval Academy.  That one was under a low-powered microscope, its eye and internal organs just barely visible.  To the macro scale world naked eye water fleas are visible as tiny swimming specks.  They are common in temperate freshwater ponds and wetlands throughout north America, Europe and Australia.   

This monstrous free Daphnia stares directionless with its single lidless black eye.  Its clear shell-like carapace reveals every organ, every muscle and nerve fiber… and filling its abdominal cavity, a number of twitching, kicking, spinning daphnia embryos. 

“I think we stunned it,” diagnosed Lyra.  “Jonathan, do you know what this means?”

“I do, indeed,” I said, knowing full well at what Lyra was hinting.  “But this time you won’t be going alone!”

Barron helps us into our suits and helmets.  The equipment is coated with a thin film of oil that we rendered from fatty bodies harvested from the algal protist recently brought aboard.  The oil negates the cohesive nature of water that occurs when air and water meet, and will permit us to slip effortlessly through the otherwise impenetrable surface tension.

“Skipper, if you’ll allow me,” says Barron as he places the brass diving helmet over my head, “I’d like to go outside myself and hammer out the starboard manipulator.  Looks like the extender arm was bent when we collided with the beasty.”

I grant Barron permission to make the repair dive, but with the understanding that he stay in line-of-sight with Gyro in the pilothouse.

1500 hours…

Lyra and I drop through the diving portal on the Cyclops’ underside.  We swim toward the stunned animal, then turn to circumnavigate it.  I glance back over my shoulder at the ship.  Barron is outside now, affecting repairs on the starboard manipulator arm assembly.  I can see Gyro through the pilothouse windows, his interest trained on Barron.  I am confident that both men are observing safety protocols.  I turn my attention back to the subject.

Daphnia has a range of normal sizes.  This one is about four times the size of Cyclops.  The first impression is as if looking at a complex animal with the benefit of fluoroscopic vision. We peer easily through her clear shell, and can survey all of the internal organs.

The Daphnia’s eye, upon closer examination, is not a single black structure as I originally believed; it is instead a cluster of light receptors connected to the creature’s brain by a visible bundle of nerves, and controlled by a network of muscles, very much like the far more complex human eye.

Even stunned, the animal’s jaws are constantly grinding, ready to crush and swallow the small food organisms it prefers. Her digestive system is an elongated S-shape that fills the center of the main body, and is packed with green organisms in various stages of digestion.  These are the same algal protists that make up the usual diet of most freshwater planktonic crustaceans.    

The daphnia’s heart is beating quickly, pumping a clear fluid through the animal’s body, presumably to deliver oxygen to muscles and organs. And in the lower abdominal chamber a brood of wee daphnia is plainly visible…babies!  It looks crowded in there.  Birth time can’t be far off.  I am struck by the impression that the embryos are looking out through their mother’s transparent exoskeleton at us.

We continue our swim around the creature for perhaps three quarters of an hour before Lyra signals that our air tanks are below 25% volume, giving us about fifteen minutes to leisurely complete one more circle before heading back to the ship. 

At that moment a flashing light comes from the direction of the Cyclops.  I turn toward my ship to see the forward lamps powering on and off in rapid succession –the signal that we should return as fast as we can swim.

We kick with a steady, controlled rhythm.  I cannot help trying to imagine why Gyro has recalled us early from the dive.  Perhaps he has reason to suspect a predator is nearby, or other nature peril.  We kick our way closer and closer to the ship, one micron at a time.  Finally, we are under the command section and the warm, welcome light of the diving room is stabbing down through the open portal.  Lyra ascends first.  As I wait, alone here in aquatic micro space, I imagine this would be moment we come under attack by some enormous predator.  I would be flung away from the ship with only a few minutes of air remaining.  But my imagination is proven wrong.  Barron’s arm appears through the aperture.  I grab his forearm and allow him lift me up into the safety of the ship.

1600 hours…

“Skipper, I can’t explain it,” Gyro says as we stowed our diving gear.

“Please try,” I press.  I was irritated about having to cut our dive short, and hadn’t yet received anything that approached a coherent excuse or explanation.

Gyro shrugs.  “I don’t think we are alone.”  The words bounced around the diving room with a metallic timbre.  “I can’t think of any other explanation.”

“Explanation for what, Mr. Gyro?”

“For what happened.  See, I was in the pilothouse, like you ordered.  Keeping at eye outside on Barron, like you told me.  He was almost done with the repairs when I felt something in my ears, in my head, like a pressure change.  It was very fast, so I ignored it.  There were no alarms, so I didn’t think any more about it…until…”

“Until what?” I insist.

“I saw that Barron was finished.  He gave me the okay sign, so I started down here to help him through the aperture.  As I was passing the lab I thought I saw something in there, like a shadow that shouldn’t be there.  At first I thought maybe it was the light coming through the porthole playing tricks on me.  Then I stuck my head through the door.  And it was gone.”

“Gyro,” I ask as patiently as I can muster, “what was gone?”

“That damaged algae cell we brought on board,” explains Gyro.  “We ate the chloroplast from it for breakfast, and boiled down the fat-bodies for oil.   I think Lyra wanted to save it for a couple more days to study.”

“That’s right,” confirms Lyra.  “I want to examine the other organelles before discarding it overboard.”

“Well, you won’t have the chance,” Gyro proclaims, “because the whole thing, except for what we used, is gone.”

“What do you mean, ‘gone?’” Lyra asks.

“Every bit of it, including the parts you’d set aside… completely gone.  Something took them, or they walked out of here on their own.  There isn’t a drop of cytoplasm in the examination tray.”

“That’s when you signaled us?” I asked.

“No, Skipper,” Gyro answers.  “While Barron was getting out of his gear I took a look around.  I found something up on the main deck.  The aft hatch had been opened and then closed again.  There was a puddle on the deck just inside the airlock.  That’s when I signaled you.”

A chill creeps down my back.  “Let’s have a look,” I say.

We find the aft hatch just as Gyro had described, secure with the pressure seals in their locked position, but it has clearly been opened recently.  At the base of the hatch the deck is wet with a large puddle and several smaller puddles.  Though it defies logic, someone, or something has used this exit to enter the ship, collect the remains of the dead algal protist, and then leave.  Since all crewmembers have been accounted for, something unknown was aboard the Cyclops. 

Lyra spends several moments bent over the small puddles, then stands and whispers into my ear: “I’m pretty sure those are footprints.  But…

“But what?” I ask.

“They’re not human.”